38 PLATE XV. 



specimen has one of the ternate radii bifurcated, a 

 variation not uncommon among the adult spicula of 

 this form in Tethva ColUngsii. 



TETHEA SCHMIDTII, Bowerlank. 



Vol. ii, p. 89, ' Mon. Brit. Spongiadse.' 



Fig. 10. Represents the specimen I received from 

 my late friend Mrs. Buckland. It was relaxed from 

 the dried condition by immersion in cold water, and 

 by that means it attained as nearly as possible its 

 natural proportions and appearance. Natural size. 



Fig. 11. A second specimen of the same species 

 which I found in the Guliot caves. It was drawn 

 from the sponge as it came from the sea, having been 

 preserved in spirit. Natural size. 



This specimen has small Balani parasitical on its 

 surface, indicating that it had probably existed several 

 years. 



Fig. 12. - - A fusiformi-acerate skeleton spiculum. 

 X 80 linear. 



Fig. 13. A fully-developed, attenuato-recurvo, 

 patento-ternate, connecting spiculum. X 80 linear. 



Fig. 14. A spinulate tension and external defensive 

 spiculum from the dermal membrane. X 80 linear. 



Fig. 15. One of the large, attenuate-stellate, reten- 

 tive spicula from the dermal membrane. X 320 

 linear. 



Fig. 16. One of the minute, cylindro-stellate, reten- 

 tive spicula from the dermal membrane. X 320 

 linear. 



TETHEA LYNCURIUM, Johnston. 



Vol. ii, p. 92, ' Mon. Brit. Spongiadse.' 



Fig. 17. Represents a specimen preserved in spirit 

 as it came from the sea at Plymouth. Natural size. 

 Fig. 18. A second specimen from the same locality, 



